Propeller.



M. D. THOMPSON.

PROPELLER.

APPLICATION FILED MAR. 3. 1909.

Patented Oct. 26, 1909.

E Fl WITNEEEEE MILTON D. THOMPSON, OF SOUTH PORTLAND, MAINE.

PROPELLER.

Specification of Letters Patent.

Patented Oct. 26, 1909.

Application filed March 3, 1909. Serial No. 481,115.

To all whom 'it may concern:

Be it known that I, MILTON D. THOMPSON, a citizen of the United States, residing at South Portland, in the county of Cumberland and State of Maine, have invented new and useful Improvements in Propellers, of which the following is a specification.

My invention relates to improvements in propellers and its object is to provide a propeller the blades of which are adapted to open and close automatically, opening when the propeller shaft is set in motion and clos ing when it stops.

It also relates to means for permanently locking the blades in operative position.

In the drawings herewith accompanying and making part of this application, Figure 1 is a vertical sectional view of my improved propeller, a portion of one of the propeller blades being broken out to show the position of the other behind it; Fig. 2 is a detail view in elevation of the blade operating plunger and Fig. 3 is a transverse sectional view of Fig. l, the extremities of the blades being broken off.

Same letters of reference refer to like parts.

In said drawings A is a casting or mount to support the propeller blades, adapted to be secured in any convenient manner to the propeller shaft B. rIhe mount A is provided with laterally extending slots C for the reception of the propeller blades, which are pivotally mounted on a bearing D extending transversely through the mount and through the propeller blades. In the upper end of the mount isa plunger E to the under side of which in any convenient manner, as for example, by a. pivot pin F passing through downwardly projecting ears G, is secured a toggle lever H--IL the extremity of one end being pivotally secured to the propeller blade I and the other to the propeller blade J. On the end of the mount A is a removable cap K between which and the plunger E is a spring L tending constantly to force the plunger down, whereby the toggle, being eccentrically secured to the propeller blades, causes them to close in toward the mount- The propeller shaft B may be made hollow and provided with a plunger M having on the end a locking pin N which is adapted to be moved into a pnl-receivingrecess O formed in the adjacent faces of the two propeller blades thereby locking the blades permanently in open position. The plunger M can be operated by means of a sliding sleeve P and connecting pin Q projecting through a slot R in the shaft.\ 'Ihe sleeve can be made water-tight by means of a packing S.

The operation of my improved propeller is as follows. Vhen the propeller shaft is stationary the spring causes the blades to close. When the propeller shaft is in operation the resistance of the water on the blades causes them to open against the pressure of the spring and remain open as long as the propeller is being rotated. As soon as the propeller stops the spring again causes the blades to close.

The advantages of my improved propeller are that the propeller blades close automatically when it ceases to rotate and thus lessens the resistance of the propeller. This is especially advantageous when the propeller is used as an auxiliary to a sailin vessel. Another advantage is, that the bla es when desired may be positively locked in open position. Another advantage is that both blades open and close in all cases simultaneously.

Having thus described my invention and its use I claim:-

1. A propeller comprising `a suitable mount, propeller blades pivotally mounted on a common bearing therein and movable in the plane of the propeller shaft and means tending constantly and automatically to close the blades.

. 2. A propeller comprising a suitable mount, propeller blades pivotally mounted on a common bearing therein and movable in the plane of the propeller shaft, means tending constantly to close the blades and means for positively locking the blades in open position.

3. A propeller comprising a mount, propeller blades pivotally mounted on a com, mon bearing therein and .movable in the plane of the propeller shaft, a spring actu ated plunger, a toggle secured lto said plunger, one arm adapted to open one blade, subscribing witnesses this twenty seventh the other arm adapted to open the other day of February, 1909.

blade, the power of the springl being ecient to close the blades when the propeller MILTON D' THOMPSON' l 5 is noltl in motion. In presence of- In testimony whereof, I have signed my LAUREN M. SANBoRN, name to this specification in presence of two NINA M. GARLAND. 

